This probably stems from the real course. Full course example with seven areas:
Consider a day with regular visitors playing. At the counter, they will see a sign, "Today's pin position is (1, 2, 3)", so better amateur players have an advance idea where the pins will be - front, back, left, right...
Obviously, in KIA, each green has three regions, marked with their length (in yards, probably). Region allocation and number sort differ from hole to hole. Green keepers follow this scheme when they place the pins.
I'm afraid though that this has no relevance to WGT golf - pin positions usually follow the USO settings which aren't bound to such premises. They may go to the extremes - more or less difficult for each given day of competition.